1. Field of the Invention
The present invention relates to a flash lamp device and a flash emitting device which can be used favorably in the heat treatment and so on of semiconductor substrates or liquid crystal substrates, for example.
2. Description of the Related Art
A flash lamp device comprising, for example, a flash lamp with an arc tube in which a pair of electrodes are disposed facing each other and a high voltage supply proximal conductor (to be referred to simply as “proximal conductor” herein below) known as a trigger electrode on the exterior of the arc tube of this flash lamp is widely known in the prior art. Specifically, a device with a constitution in which the proximal conductor is wound around the outer peripheral surface of an arc tube in spiral form so as to contact this surface (see Japanese Patent Application Laid-Open No. S59-189551), a device with a constitution in which a proximal conductor is provided in contact with the outer peripheral surface of an arc tube extending in the tubular axis direction along the outer peripheral surface of the arc tube (see Japanese Patent Application Laid-Open No. 2001-84962), and a device with a constitution in which a reflecting mirror provided in parallel with an arc tube doubles as a proximal conductor (see U.S. Pat. No. 3,733,599) and so on may be cited as examples thereof.
Investigations have been conducted recently into the use of flash lamp devices with such constitutions as heat sources in heat treatment devices for performing rapid heat treatment on semiconductor substrates and liquid crystal substrates, for example, and according to a heat treatment device having as a heat source a flash emitting device comprising such flash lamp devices, the surface layer part of the semiconductor substrate or liquid crystal substrate to be treated can be heated to a predetermined temperature in an extremely short amount of time.
Typically, in order to perform heat treatment on a semiconductor substrate, heating must be performed such that only the surface layer part of the semiconductor substrate rises in temperature to between 1000° C. and 1400° C., and therefore a heat treatment device having as a heat source a flash emitting device comprising flash lamp devices is specifically required to emit a semiconductor substrate to be treated with light of an energy of at least 2 J/cm2 within a short period of time such as 1 msec. In order to achieve this, the peak energy that is introduced into the flash lamp must reach 5×106 W.
However, since the light emitted from the flash lamp in the flash lamp device is of a high energy, the metallic material which constitutes the proximal conductor (also referred to as “high voltage supply proximal conductor material” herein below) sputters and scatters upon reception of this light with the result that the high voltage supply proximal conductor material becomes attached to the outer peripheral surface of the arc tube and this high voltage supply proximal conductor material is thus caused to rise in temperature. As a result, problems such as cracking of the arc tube occur due to the difference in expansion coefficient with the arc tube material, for example glass.
Further, in a flash lamp device constituted such that the proximal conductor directly contacts the outer peripheral surface of the arc tube, a problem occurs in that the proximal conductor thermally expands upon reception of light emitted from the flash lamp, causing friction between the proximal conductor and the outer peripheral surface of the arc tube such that the arc tube is damaged, and eventually, as the lamp is repeatedly illuminated and extinguished, this frictional damage leads to the breakage of the arc tube.
This problem is particularly notable in devices constituted such that the end portion of the proximal conductor contacts the arc tube.
Another problem is that as the lamp is repeatedly illuminated and extinguished, the proximal conductor is separated from the outer peripheral surface of the arc tube, creating a layer of air between the arc tube and proximal conductor which results in a deterioration of the trigger energy action such that even if the flash lamp itself is in normal working order, erroneous emissions occur and the flash lamp cannot be illuminated.